Lamp socket



Inventor": Thomas I. Malin,

Hls Attorney.

Patented Feb. 11 1941 PATENT OFFICE LAMP SOCKET Thomas I. Maslin, Bloomfield, N. J., assignor to General Electric Company, a corporation of New York Application August 28, 1939, Serial No. 292,170

My invention relates to sockets for incandescent lamps of the screw base type and has for its object a simple and reliable socket which is self-locking to secure the lamp in place.

In carrying out my invention, I utilize a screw contact providing a single turn in the form of a helical ring, the ring being discontinuous to provide for flexure of one side to lock the lamp when the lamp base is screwed tightly into position.

For a more complete understanding of my invention, reference should be had to the accompanying drawing, Fig. l of which is a plan view of an elongated push button having a lamp socket embodying my invention; Fig. 2 is a sectional view taken along the line 2--2 of Fig. 1 looking in the direction of the arrows, while Fig. 3 is a perspective view of the ring-shaped self-locking contact.

Referring to the drawing, I have shown my invention in one form as applied to the movable button ID of an electric push button switch which button, it will be understood, cooperates with suitable electric contacts (not shown) so that when the button is depressed, the contacts are engaged or disengaged to control an electriccircuit. It is desirable at times to provide such buttons with illumination which is conveniently effected by mounting a small incandescent lamp in the button itself together with auxiliary contacts leading to the lamp base and cooperating with auxiliary stationary contacts when the button is pressed to light the lamp, or contacts so arranged that the lamp circuit will be opened when the button is pressed.

The button I is made from a suitable electrically insulating material such as a molded compound. It is provided with a central bore II forming a socket to receive the lamp socket which is closed by a screw cap I2 extending over the lamp. Parts only of the cap I2 and the lamp ID are shown for purposes of clarity. In the center and at the bottom of the socket II is the usual central rigid electrically conducting contact M which leads out of the push button and is secured to the push button by means of a suitable rivet IS.

The screw terminal l6 for the socket. into which terminal the lamp is screwed into engagement with the central contact I4, is in the form of a ring shaped into a single turn helixv as shown clearly in Fig. 3. This ring has a strap extension II, the ring and strap being preferably made of a suitable electrically conducting spring material such as bronze, which extends outside of the button and then has a lateral extension l8 in parallel relation with the button and secured to the button by a rivet l9.

At a point diametrically opposite the strap I1 is a second supporting projection 20 on the ring l6 which extends into a recess or notch 2| in the wall of the socket. As shown in Fig. 2, this projection 20 normally engages the outer side of this recess, i. e., the left-hand side, as seen in Fig. 2. The recess however is larger than the projection to provide for ease of assembly.

The ring l6, furthermore, is discontinuous at a point adjacent the projection 20, a slot 22 being provided whereby one-half or section 23 of the ring is provided with an end 24 which is free to move in response to flexure of that side.

With this arrangement, when the threaded lamp base 25 is screwed into the socket and engages the central contact l4 and thereafter is turned still further to tighten it, the unsecured section 23 of the ring flexes and is forced out,- ward somewhat in a direction away from the central contact, the other half or section being held or anchored by the projection 20. As a result of this action, the section 23 is forced out of true thread mating relation with the lamp base. This produces a frictional locking effect whereby the lamp is secured against any tendency to rotate in a direction to loosen it, such as might be caused by vibration or jars. The lamp however can be forcibly turned to remove it without difiiculty.

It will be understood that, as shown in Fig. 3, the spring ring member I6 normally has its two oppositely disposed adjacent ends formed by the slot 22 in helical alignment with each other: i. e., the two ends arenot displaced from the single turn helix in a lateral direction parallel with the axis of the helix. Consequently, the lamp basecan be screwed loosely'into the ring without interference from -'either one of the 4 spaced ends of the ring. When the end 24 is flexed in a direction away from the central contact, it engages the other one of the two adjacent threads of the lamp base, between which threads the ring is held. This produces a frictional lock- 5 ing action and the end 24 may be sharp enough to dig into the metal of the other adjacent thread.

To facilitate assembly, the base I 0 is provided with a recess or slot 26 extending from the end of the socket to the strap I! and somewhat wider than the strap. This provides for insertion of the ring terminal It in place in the socket after which it is secured by means of the rivet l9.

While I have shown a particular embodiment of my invention, it will be understood, of course,

that I do not wish to be limited thereto, since many modifications may be made and I, therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. A lamp socket comprising a supporting socket member made of electrically insulating material, a central electrically conducting con-. tact on said supporting member, a discontinuous helical member having a diameter and thickness to fit loosely between two adjacent threads on the lamp base, said helical member being discontinuous to form two oppositely disposed adjacent ends normally in helical alignment with each other, means securing said helical member to said supporting member so that one of said ends and one portion of said helical member are secured against fiexure away from said central contact and the other end is free to flex away from said central contact when the lamp base is screwed into said helical member against said central contact with a thread 01. the base wedged against said portion of said helical member, said other end being flexed by said thread away from said central contact into engagement with the adjacent thread on the lamp base thereby frictionally to lock the lamp base in the socket.

2. A lamp socket comprising a supporting socket member made oi electrically insulating said ends to said supporting member so that said 15 end and one half of said spring member are secured against fiexure away'irom said central contact and the other end is free to fiex away from said central contact when the lamp base is screwed intov said spring member tightly against 20 said central contact with a thread of the base wedged against said half of said spring member, 4

said other end being flexed by said thread away from said central contact into engagement with the adjacent thread on the lamp base thereby Z frictionally to lock the lamp base in the socket.

/ THOMAS I. MASLIN. 

